Fifteen DO, PG 1159 and related white dwarf stars in the SDSS, including two DO stars with ultra-high excitation ion lines

¹ New Mexico State University, Apache Point Observatory, PO Box 59, Sunspot, NM 88349, USA
² Mt. Suhora Observatory, Cracow Pedagogical University ul. Podchorążych 2, 30-084 Cracow, Poland
³ US Naval Observatory, PO Box 1149, Flagstaff, AZ 86002-1149, USA
⁴ Steward Observatory, University of Arizona, 933 N. Cherry Ave. Tucson, AZ 85721-0065, USA
⁵ Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA

Corresponding author: J. Krzesiński, jurek@apo.nmsu.edu

Received: 18 November 2003
Accepted: 8 January 2004

Abstract

We report on observations of 15 spectroscopically-identified DO stars from the Sloan Digital Sky Survey (SDSS) database, 13 of which are new discoveries. There are four PG 1159 type stars, two DO stars showing ultra-high excitation ion features (C, N, O, O, Ne, Ne) likely formed in stellar winds, 6 normal DO stars, one DBO and DBAO star, and one DAO star, which may also be magnetic. Since roughly 60 DO stars were known up to now, this new finding substantially increases the number of known DO white dwarf stars and we expect to at least double the current number of known DO stars by the end of the SDSS. We present each spectrum and provide catalog information (magnitudes, proper motion, coordinates) for each star.